US8960015B2 - Load test stand - Google Patents

Load test stand Download PDF

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Publication number
US8960015B2
US8960015B2 US14/178,518 US201414178518A US8960015B2 US 8960015 B2 US8960015 B2 US 8960015B2 US 201414178518 A US201414178518 A US 201414178518A US 8960015 B2 US8960015 B2 US 8960015B2
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United States
Prior art keywords
test stand
load test
frame
flange
spring
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US14/178,518
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US20140224035A1 (en
Inventor
Thomas Klaffert
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MBDA Deutschland GmbH
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MBDA Deutschland GmbH
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Assigned to MBDA DEUTSCHLAND GMBH reassignment MBDA DEUTSCHLAND GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KLAFFERT, THOMAS
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M99/00—Subject matter not provided for in other groups of this subclass
    • G01M99/007—Subject matter not provided for in other groups of this subclass by applying a load, e.g. for resistance or wear testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M13/00—Testing of machine parts
    • G01M13/02—Gearings; Transmission mechanisms
    • G01M13/027—Test-benches with force-applying means, e.g. loading of drive shafts along several directions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/22—Investigating strength properties of solid materials by application of mechanical stress by applying steady torsional forces

Definitions

  • the present invention relates to a load test stand, preferably for simulating load cycles.
  • a load test stand preferably for simulating load cycles.
  • a proof of the performance obtained while adhering to the specified data is required.
  • rudder systems or wing servo systems for missiles it is necessary to determine, among other things, the actual values for the servo angle and/or the servo speed and/or the servo acceleration in both directions of motion as well as the bandwidth that is obtained for the specified load torques and inertias on the output side under all required environmental conditions.
  • the simultaneous application of lateral forces on the output shafts of the servo system may also be required.
  • load test stands In order to simulate realistic load cycles for servo systems integrated into missile systems, active servo motor-driven or servo hydraulic-powered load test stands have already been developed. These load test stands can apply, as a function of the calculated requirements or closed simulation loops, realistic external load cycles on the output shafts of a servo system that is to be tested. Due to their very high overall cost and the limited adaptability of the load dynamics that can be obtained with different sizes of servo systems, these load test stands are available only on a limited scale.
  • a torsion bar 10 or also a combination of several interconnected torsion bars 10 are flanged to each output shaft 6 of the servo system 4 that is to be tested.
  • the torsion bar 10 injects a torque in proportion to the change in the servo angle. Inherent deviations from the linearity can be detected by means of accurate measurements of the load test stand 1 . At the same time the calibration effort with respect to such measurements is very low compared to that of active load test stands.
  • the torsion bars 10 are clamped in a force fitted way, the conditions for zero backlash and the necessary robustness with respect to environment factors are met in compliance with the test specification.
  • the net weight which is significantly less than that of active test stands, offers better conditions for combining with other test equipment, like shakers, climate chambers, etc., but which can be used to date only conditionally for other structural and mechanical reasons, which will be described below.
  • the use of almost linear torsion springs assumes that, on the one hand, the spring constant, which is to be implemented by means of the design, meets the requirements of the test specification for the servo systems, and, on the other hand, that their dimensioning permits sufficiently large servo angle ranges to be covered in compliance with all of the proofs required.
  • Exemplary embodiments of the present invention are directed to a load test stand, which has compact dimensions while at the same time is easy and cost-effective to produce, and which makes it possible to test servo systems in a fast and reliable way.
  • exemplary embodiments of the present invention are directed to a load test stand, which exhibits a passive design.
  • the load test stand comprises a frame, a flange and a spring mechanism.
  • the spring mechanism is mounted on the frame and comprises a, preferably symmetrical, arrangement of at least four spring elements.
  • the flange is mounted preferably by the spring mechanism.
  • the spring mechanism comprises frame points connecting the frame to the spring mechanism, and comprises articulation points connecting the flange to the spring mechanism.
  • the flange can be coupled, by means of an adapter, to the output shaft of a servo system that is to be tested.
  • the use of the spring mechanism allows the flange to be positionable vertically and horizontally and with respect to its neutral angle position. This arrangement enables an alignment with the output shaft of the servo system in a particularly advantageous manner.
  • the axially elastic suspension of the flange by means of the spring mechanism makes it possible to prevent preferably undefined axial forces from being introduced into the output shaft, which could be the case, for example, in the event of temperature fluctuations. Therefore, the spring mechanism acts advantageously as a compensation element.
  • the use of the spring mechanism makes it possible to apply defined lateral forces to the output shaft of the servo system to be tested in a particularly advantageous manner. Therefore, the load test stand, according to the invention, can be used preferably in a very flexible way in order to test different load conditions.
  • the frame points are mounted in at least one substructure.
  • the substructure and the spring mechanism form an adjustable and/or calibratable independent module.
  • the module can be attached, preferably by means of a universal interface, to the frame.
  • the use of the module makes it possible to create a rigid test stand, because the module can be arranged close to the servo system to be tested.
  • the spring mechanism is situated advantageously very close to the servo system.
  • this arrangement enables preferably the spring mechanism to be connected rigidly with zero backlash to the servo system.
  • the load test stand allows the possibility of adjusting the flange to the output shaft of the servo system along a first axis.
  • a position of the flange along a second axis can be adjusted by means of a change in the opposite direction of the position of at least two opposite frame points of different substructures.
  • the second axis is aligned preferably perpendicularly to the aforementioned first axis. Therefore, the load test stand can enable an independent alignment of the flange along two axes that are perpendicular to each other in a particularly advantageous manner.
  • a position of the flange along a third axis can be adjusted by means of an equidirectional change in the position of at least two opposite frame points.
  • the third axis is advantageously perpendicular to the above described two axes, so that it is possible to align the flange independently along three axes.
  • the frame points and/or the bearing points In order to change the position of the frame points and/or the bearing points, it is preferably provided that there are actuators.
  • the position of the frame points and/or the bearing points can be changed in an advantageous way with these actuators. Therefore, a specified load can be applied on the flange and, thus, on the servo system by means of the test stand, so that the load test stand can be used in a very flexible way.
  • the frame points and/or the bearing points can also be adjusted by hand.
  • a lateral force can be applied to an output shaft, which is part of the servo system and can be connected to the flange, by changing the position of at least one frame point.
  • Such an arrangement also allows the load test stand, according to the invention, to test the servo system for the purpose of determining how the servo system responds to lateral forces acting on the output axes. Therefore, the load test stand enables in an advantageous way a very comprehensive testing of the servo system.
  • a spring characteristic of the spring elements can be adjusted by means of a change in the position of the articulation points and/or the frame points.
  • the spring characteristic of the spring elements can be adjusted by changing the relative position of the frame points to the articulation points of the spring elements.
  • the spring characteristic can be adjusted in such a way that it exhibits linear ranges.
  • the spring characteristic can be adjusted in such a way that it has at least linearizable sections. It is advantageous that the spring characteristic comprises a plurality of linear and/or linearizable sections. The advantageous use of linear and/or linearizable sections of the spring characteristic allows very simple test procedures to be carried out, because the spring force and the torsional angle are in proportion to each other.
  • the load test stand comprises a measuring system at the flange.
  • the measuring system is designed as an angle measuring system. Such an arrangement makes it possible to measure accurately and easily the response of the servo system. Therefore, the load test stand allows a fast and easy testing of the servo system.
  • the measuring system in the calibrated state forms the reference for the spring characteristic of the spring elements of the spring mechanism.
  • the load test stand exhibits preferably inertial bodies, wherein said inertial bodies can be, in particular, simulations of rudder units or wing units, which normally would be movable with the servo system to be tested.
  • the flange which is elastically suspended by means of the spring mechanism in the axial direction, makes it possible to compensate for tolerances axially to the output shafts of the servo system.
  • the spring mechanism is used to compensate for the temperature-dependent changes in tolerances.
  • other components can also be disposed on the frame, in addition to the modules.
  • the additional components and/or the modules can be arranged at arbitrary positions around the servo system.
  • the module, in particular the substructure of the module comprises a protective casing, a transverse guide of the spring elements, the integration of end stops and/or safety devices when coupling to and uncoupling from the output shaft of the servo system.
  • the substructure of each module can be integrated in the frame of the load test stand. The net result of this approach is an advantageous dynamic rigidity, so that multi-axis vibration tests can also be run with the load test stand.
  • FIG. 1 a schematic view of a load test stand according to the state of the art.
  • FIG. 2 a schematic view of the operating principle of the load test stand according to one exemplary embodiment of the invention.
  • FIG. 3 a first schematic view of the load test stand according to the exemplary embodiment of the invention.
  • FIG. 4 a second schematic view of the load test stand according to the exemplary embodiment of the invention.
  • FIG. 5 a graph showing the spring characteristic of a torsion bar.
  • FIG. 6 a graph showing the spring characteristic of the test stand according to the exemplary embodiment of the invention.
  • FIG. 7 a graph showing an alternative spring characteristic of the load test stand according to the exemplary embodiment of the invention.
  • FIG. 1 shows a test stand 1 according to the state of the art.
  • This prior art test stand has already been described in the introductory part of the specification.
  • the use of torsional bars 10 makes it necessary for the size of the frame 13 to be large. Therefore, the dimensions of the test stand 1 are considerably larger than the dimensions of the servo system 4 to be tested.
  • FIG. 2 shows in schematic form the operating principle of the test stand 1 according to one exemplary embodiment of the invention
  • FIG. 3 is a schematic view of an implementation of the principle depicted in FIG. 2
  • the spring mechanism 2 forms a suspension for a flange 5 , to which an output shaft 6 of a servo system 4 , which is to be tested, can be connected.
  • Each spring element 3 is connected to the flange 5 at an articulation point 12 and is connected to the frame 13 of the test stand 1 by means of a frame point 11 .
  • the frame points 11 are mounted in a plurality of substructures 14 , so that the net result is a plurality of independent modules 7 .
  • An alignment of the flange 5 is possible by changing the position of the frame points 11 and/or the articulation points 12 . In this way it is also possible to apply lateral forces to an output shaft 6 , which is connected to the flange 5 , in that following alignment and connection with the output shaft 6 , the flange 5 is moved once more into its position. In this case the output shaft 6 serves as the abutment, so that the output shaft 6 has to absorb a lateral force.
  • the flange 5 can be aligned along a first axis 20 , a second axis 30 and a fourth axis 40 .
  • first axis 20 and the second axis 30 are parallel to the drawing plane and are perpendicular to each other.
  • the third axis 40 is an axis of rotation and is perpendicular to the first axis 20 and the second axis 30 , so that it is possible to rotate the flange 5 inside the drawing plane.
  • the two frame points 11 of a substructure 14 can be moved outwards, i.e. away from the drive axis 6 , in order to move by this technique the flange 5 in the same direction as the frame points 11 .
  • the frame points 11 of the same substructure were to be moved in the opposite direction, for example, one frame point 11 inwards and another frame point 11 outwards, then the position of the flange 5 would not change.
  • the prestress of the spring mechanisms 2 can be enlarged in this way, because the respective spring excursion between the frame point 11 and the articulation point 12 is elongated.
  • two opposite frame points 11 of different substructures 14 are moved in opposite directions, then it is possible to move the flange 5 along the second axis 30 .
  • two frame points 11 can be moved away from each other, in order to move the flange 5 along the second axis 30 in the direction of the frame points 11 .
  • the inventive load test stand 1 can be adjusted very flexibly and can, therefore, be used for a plethora of applications.
  • FIG. 4 shows an example of the configuration of the inventive test stand 1 , according to the exemplary embodiment.
  • This test stand comprises a frame 13 , to which a plurality of independent modules 7 are attached.
  • the modules 7 are in conformity with the configuration of the modules shown in FIGS. 2 and 3 .
  • Each of the modules 7 is connected to the flange 5 (which cannot be seen in FIG. 4 ), so that the flange 5 is mounted on the module 7 in such a way that the modules 7 can perform a tolerance equalization.
  • the effects of temperature fluctuations can be eliminated by this technique, so that the temperature fluctuations do not appear as a source of error in the load test stand 1 .
  • Attached to the flange 5 are a plurality of measuring systems 8 , which can determine the forces and/or the torques applied by the servo system 4 to the flange 5 .
  • inertial bodies 9 can be mounted on the measuring systems 8 .
  • These inertial bodies are designed preferably to simulate rudder inertias or wing inertias.
  • the influence of these masses of inertia, to which the servo system 4 will be exposed during normal operation can be simulated with the inventive load test stand 1 of the exemplary embodiment.
  • the inertial bodies 9 In order to be able to replace the inertial bodies 9 easily and quickly the inertial bodies are mounted in a floating manner on the measuring system 8 .
  • FIGS. 5 , 6 and 7 show three different spring characteristics.
  • FIG. 5 shows a first spring characteristic 300 of a torsion bar
  • FIGS. 6 and 7 show a second spring characteristic 400 of a spring element and a third spring characteristic 500 of a spring element.
  • This situation is illustrated by means of graphs, which always show an instantaneous axis 100 and a torsional axis 200 .
  • the first spring characteristic 300 runs almost linear, which is the major advantage of a torsion bar, a feature that justifies its frequent use in the state of the art.
  • FIGS. 6 and 7 show that even the second spring characteristic 400 as well as the third spring characteristic 500 always exhibit linear and/or linearizable ranges.
  • a first linear range 401 and a second linear range 402 can be found within the second spring characteristic 400 in FIG. 6 .
  • the inventive use of the above-described load test stand 1 makes it possible to adjust very precisely the spring characteristic of the individual spring elements 3 by changing the frame points 11 and the articulation points 12 . Therefore, it is possible to adjust the spring characteristics of the spring elements 3 in such a way that they fall within the linear ranges 401 , 402 , 501 , 502 .
  • Such an arrangement makes a measurement with the load test stand, according to the invention, very easy to perform, because an applied torque is almost in proportion to the measured torsion.
  • the inventive load test stand 1 according to the exemplary embodiment shown in the figures, has the following advantageous possibilities:

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
US14/178,518 2013-02-13 2014-02-12 Load test stand Active US8960015B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP13000733.9-1557 2013-02-13
EP13000733.9A EP2767814B1 (de) 2013-02-13 2013-02-13 Lastprüfstand für ein Stellsystem mit einer Abtriebswelle
EP13000733 2013-02-13

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US20140224035A1 US20140224035A1 (en) 2014-08-14
US8960015B2 true US8960015B2 (en) 2015-02-24

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106092558A (zh) * 2016-08-23 2016-11-09 北京航天动力研究所 一体式液体火箭发动机高速涡轮泵转子动特性试验装置
US11226262B2 (en) * 2016-10-21 2022-01-18 Mg-Valdunes Apparatus for testing a shaft and/or a mechanical part on the shaft and use of such an apparatus

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105388009B (zh) * 2015-12-30 2017-10-24 盛瑞传动股份有限公司 弹簧耐久检测装置
DE102016210193A1 (de) * 2016-06-09 2017-12-14 Zf Friedrichshafen Ag Prüfvorrichtung für einen Linearaktor
CN112816193B (zh) * 2020-12-30 2023-05-02 嘉兴毅拓汽车科技有限公司 一种用于电控执行器的可变负载耐久测试装置及测试方法
CN114720039B (zh) * 2022-06-02 2022-08-26 四川升拓检测技术股份有限公司 一种测量精轧螺纹钢锚下有效预应力的方法
CN120171785B (zh) * 2025-05-22 2025-08-05 北京航辰机载智能系统科技有限公司 一种多模式切换的电液伺服测试系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1574491A (en) 1921-08-12 1926-02-23 Gen Railway Signal Co Torque-testing device for semaphore signals
US4171803A (en) * 1977-09-12 1979-10-23 Smith Roger D Karate practice breaking board
JPS60133350A (ja) 1983-12-21 1985-07-16 Tokyo Koki Seizosho:Kk 捩り試験治具
DE3840261A1 (de) 1988-11-30 1990-05-31 Deutsche Forsch Luft Raumfahrt Belastungsvorrichtung
DE102006029556A1 (de) 2006-06-26 2007-12-27 Gtm Gassmann Testing And Metrology Gmbh Prüfvorrichtung für Impulsschrauber

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1574491A (en) 1921-08-12 1926-02-23 Gen Railway Signal Co Torque-testing device for semaphore signals
US4171803A (en) * 1977-09-12 1979-10-23 Smith Roger D Karate practice breaking board
JPS60133350A (ja) 1983-12-21 1985-07-16 Tokyo Koki Seizosho:Kk 捩り試験治具
DE3840261A1 (de) 1988-11-30 1990-05-31 Deutsche Forsch Luft Raumfahrt Belastungsvorrichtung
DE102006029556A1 (de) 2006-06-26 2007-12-27 Gtm Gassmann Testing And Metrology Gmbh Prüfvorrichtung für Impulsschrauber

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106092558A (zh) * 2016-08-23 2016-11-09 北京航天动力研究所 一体式液体火箭发动机高速涡轮泵转子动特性试验装置
CN106092558B (zh) * 2016-08-23 2018-05-22 北京航天动力研究所 一体式液体火箭发动机高速涡轮泵转子动特性试验装置
US11226262B2 (en) * 2016-10-21 2022-01-18 Mg-Valdunes Apparatus for testing a shaft and/or a mechanical part on the shaft and use of such an apparatus

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Publication number Publication date
EP2767814B1 (de) 2019-08-28
US20140224035A1 (en) 2014-08-14
EP2767814A1 (de) 2014-08-20

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